Preparation of Zr(Mo, W)2O8 with a larger negative thermal expansion by controlling the thermal decomposition of Zr(Mo, W)2(OH, Cl)2∙2H2O
| Parent link: | Scientific Reports Vol. 8.— 2018.— [5337, 7 p.] |
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| Collectivité auteur: | |
| Autres auteurs: | , , , , , , , , |
| Résumé: | Title screen Solid solutions of Zr(Mo,W)2O7(OH,Cl)2∙2H2O with a preset ratio of components were prepared by a hydrothermal method. The chemical composition of the solutions was determined by energy dispersive X-ray spectroscopy (EDX). For all the samples of ZrMoxW2−xO7(OH,Cl)2∙2H2O (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, and 2.0), TGA and in situ powder X-ray diffraction (PXRD) studies (300-1100 K) were conducted. For each case, the boundaries of the transformations were determined: Zr(Mo,W)2O7(OH,Cl)2∙2H2O → orthorhombic-ZrMoxW2−xO8 (425-525 K), orthorhombic-ZrMoxW2−xO8 → cubic-ZrMoxW2−xO8 (700-850 K), cubic-ZrMoxW2−xO8 → trigonal-ZrMoxW2−xO8 (800-1050 K for x > 1) and cubic-ZrMoxW2−xO8 → oxides (1000-1075 K for x ≤ 1). The cell parameters of the disordered cubic-ZrMoxW2−xO8 (space group Pa-3) were measured within 300-900 K, and the thermal expansion coefficients were calculated: −3.5∙10−6 - −4.5∙10−6 K−1. For the ordered ZrMo1.8W0.2O8 (space group P213), a negative thermal expansion (NTE) coefficient −9.6∙10−6 K−1 (300-400 K) was calculated. Orthorhombic-ZrW2O8 is formed upon the decomposition of ZrW2O7(OH,Cl)2∙2H2O within 500-800 K. |
| Langue: | anglais |
| Publié: |
2018
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| Sujets: | |
| Accès en ligne: | https://doi.org/10.1038/s41598-018-23529-6 |
| Format: | Électronique Chapitre de livre |
| KOHA link: | https://koha.lib.tpu.ru/cgi-bin/koha/opac-detail.pl?biblionumber=667037 |